This application for a competing renewal grant proposes to synthesize and organize existing knowledge regarding HIV transmission through behavior change. This synthesis will be achieved through a continuing series of seven theoretically guided and methodologically rigorous meta-analyses. Study 1 will gather and synthesize studies evaluating HIV prevention studies in developing regions and countries. Study 2 will gather and synthesize studies evaluating prevention of HIV in IDU and drug-use behaviors. Study 3 will examine gender differences in response to intensive HIV risk-reduction efforts. Study 4 will determine how the content of risk-reduction interventions relates to the risk-reduction effects obtained. Study 5 will evaluate the success of mass-media strategies for HIV prevention. Study 6 will compare HIV prevention effects to those obtained across public-health change literatures. Study 7 will examine how risk behaviors are caused by or cause risk related attitudes and other cognitions. By carefully summing up the evidence to date on these important and quickly growing literatures, these meta-analyses will inform public health officials, community-based interventionists, and scientists about which interventions work best, which components of interventions have the largest impact, and the circumstances under which HIV risk-reduction interventions are most likely to be successful. [unreadable] [unreadable]